1. Field of the Invention
The present invention relates to a firing furnace, a manufacturing method of a ceramic member using this firing furnace, a ceramic member, and a ceramic honeycomb filter.
2. Discussion of the Background
There have been proposed various exhaust-gas purifying honeycomb filters and catalyst supporting bodies which are used for purifying exhaust gases discharged from internal combustion engines of vehicles, such as a bus, a truck and the like, construction machines and the like.
With respect to such an exhaust-gas purifying honeycomb filter or the like, there has been used a honeycomb structural body made of a non-oxide ceramic porous material such as silicon carbide having superior heat resistance.
Conventionally, for example, Japanese Patent Laid-open Publication No. 2001-48657 and Japanese Patent Laid-open Publication No. 63-302291 (1988) have disclosed firing furnaces for manufacturing the non-oxide ceramic member of this type.
The firing furnace for manufacturing the non-oxide ceramic member of this type or the like is provided with a muffle, a heater and the like that are installed in the furnace, and a heat insulating layer made of a heat insulating member that is placed so as to enclose the muffle and the heater.
In the firing furnace of this type, the heat insulating layer is constituted by a plurality of layers, and these heat insulating layers are fixed by stoppers. These stoppers are made of, for example, carbon that is superior in heat resistance. With respect to the heat insulating layer, the inner layer is made of carbon that is superior in high-temperature heat resistance, while the outermost layer is made of a material other than carbon since the temperature thereof is lower than that of the inner layer. In many cases, this layer is prepared as, for example, a layer made of ceramic fibers such as alumina fibers or the like (hereinafter, referred to as ceramic fiber layer).
The contents of Japanese Patent Laid-open Publication No. 2001-48657 and Japanese Patent Laid-open Publication No. 1988-302291 are incorporated herein by reference in their entirety.